The present invention relates generally to methods of and systems for providing user input to user interfaces for computers and the like, and more particularly to a semiconductor capacitive user input device and method for controlling the position of a cursor or pointer on a display.
Pointing devices are commonly used in conjunction with computers to control the movement of graphical cursors on a display screen and to select objects and operate controls displayed on the screen. For desktop computers and workstations, the most commonly used pointing device is a mouse. As is well known, a mouse is moved over a flat surface to control the position of the pointer on the display screen. A mouse includes one or more buttons that may be pressed or clicked to perform operations on objects and controls displayed on the screen.
Recently, small laptop and notebook computers have become very popular. Laptop and notebook computers may be used in conjunction with a docking station so that a standard keyboard, mouse, and CRT display may be used for the user interface. However, laptop and notebook computers are designed to be used while traveling and away from the office or home. In such remote locations, the user does not always have available a flat surface upon which to use a mouse. Accordingly, laptop and notebook computers typically have a built-in pointing device, such as a track ball, touch pad or a pressure-actuated pointing device, such as the IBM TrackPoint (TM) device.
In addition to computers, certain television and set top box systems include a graphical user interface for enabling a user to input information to the system and change or control system settings. The user input device for such systems is typically a hand-held infrared keypad controller. Such controllers may include devices similar to those used in laptop and notebook computers to control the position of a pointer on the television screen.
Track balls, touch pads, and pressure-actuated pointing devices have certain drawbacks. For example, while track balls are compact, they require considerable finger movement to produce large cursor displacements at low velocities. In addition, track balls are mechanical devices that may not be well suited for operation in dirty environments. A touch pad comprises a rectangular surface that is mapped to correspond to a display screen. By touching a location on the touch pad, the user causes the computer to move the pointer to the corresponding location on the screen. Since a typical touch pad is substantially smaller than the screen, accurate positioning of the pointer can be difficult. In order to be usable, a touch pad must be large enough to permit the user to position the pointer accurately. The large size of touch pads makes them difficult or impossible to use in a hand held device such as a television remote control.
Pressure-actuated pointing devices include strain gages or transducers that detect the direction and magnitude of the force of a user""s finger on the device. The pointer is moved in a direction corresponding to the direction of the force and at a speed corresponding to the magnitude of the force. Certain individuals have trouble using pressure-actuated pointing devices to position the pointer accurately on the screen. One source of trouble is inertia, whereby the pointer continues to move after the user releases the pressure on the device.
It is an object of the present invention to provide a low-cost, small-sized, non-mechanical pointer position controlling device that overcomes the shortcomings of the prior art.
The present invention provides a method of and system for providing user input to a computer, or the like, having a display by detecting a change in fingerprint pattern of a user. In one of it aspects, the present invention provides a method of and system for controlling the X-Y position of a pointer on a display by detecting motion of ridges and pores of a fingerprint of a user and moving the pointer on the display according to detected motion of the ridges and pores of the fingerprint. In another of its aspects, the present invention provides Z axis input, such as button clicks, by detecting a widening of fingerprint ridges caused by increased pressure on a detector surface, or by detecting the lifting or the placement of the finger from or on the detector surface.
The method and system of the present invention captures successive images of the fingerprint ridges and pores and detects motion in or changes of the ridges and pores based upon the captured successive images. The method and system of the present invention captures the successive images by scanning an array of sensors, each of the sensors being smaller than the width of an individual ridge of a fingerprint. Preferably, the array of sensors is smaller than the pad of a finger of a user. In the preferred embodiment, each sensor of the array of sensors includes a capacitive element and the system captures the successive images by detecting changes in capacitance of the capacitive elements.